diff --git a/bindings/python/mapnik_value_converter.hpp b/bindings/python/mapnik_value_converter.hpp
index 5d989c0a5..42b9ba4bc 100644
--- a/bindings/python/mapnik_value_converter.hpp
+++ b/bindings/python/mapnik_value_converter.hpp
@@ -71,7 +71,7 @@ namespace boost { namespace python {
     {
         static PyObject* convert(mapnik::value const& v)
         {
-            return mapnik::util::apply_visitor(value_converter(),v.base());
+            return mapnik::util::apply_visitor(value_converter(),v);
         }
 
     };
diff --git a/include/mapnik/feature_kv_iterator.hpp b/include/mapnik/feature_kv_iterator.hpp
index 892a0c2da..060b6fc78 100644
--- a/include/mapnik/feature_kv_iterator.hpp
+++ b/include/mapnik/feature_kv_iterator.hpp
@@ -70,7 +70,7 @@ struct value_not_null
 {
     bool operator() (feature_kv_iterator::value_type const& kv) const
     {
-        return !util::apply_visitor(mapnik::detail::is_null_visitor(), std::get<1>(kv).base());
+        return !util::apply_visitor(mapnik::detail::is_null_visitor(), std::get<1>(kv));
     }
 };
 
diff --git a/include/mapnik/json/feature_generator_grammar.hpp b/include/mapnik/json/feature_generator_grammar.hpp
index 5cb957978..d909f6a84 100644
--- a/include/mapnik/json/feature_generator_grammar.hpp
+++ b/include/mapnik/json/feature_generator_grammar.hpp
@@ -126,15 +126,6 @@ struct utf8
     }
 };
 
-struct value_base
-{
-    using result_type = mapnik::value_base const&;
-    mapnik::value_base const& operator() (mapnik::value const& val) const
-    {
-        return val.base();
-    }
-};
-
 template <typename OutputIterator>
 struct escaped_string
     : karma::grammar<OutputIterator, std::string(char const*)>
@@ -150,7 +141,7 @@ struct extract_string
 
     result_type operator() (mapnik::value const& val) const
     {
-        bool need_quotes = val.base().is<value_unicode_string>();
+        bool need_quotes = val.is<value_unicode_string>();
         return std::make_tuple(val.to_string(), need_quotes);
     }
 };
@@ -173,7 +164,6 @@ struct feature_generator_grammar:
     karma::rule<OutputIterator, mapnik::value_unicode_string()> ustring;
     typename karma::int_generator<mapnik::value_integer,10, false> int__;
     boost::phoenix::function<get_id> id_;
-    boost::phoenix::function<value_base> value_base_;
     boost::phoenix::function<extract_string> extract_string_;
     boost::phoenix::function<utf8> utf8_;
     std::string quote_;
diff --git a/include/mapnik/json/feature_generator_grammar_impl.hpp b/include/mapnik/json/feature_generator_grammar_impl.hpp
index b420d74da..1d1d3c907 100644
--- a/include/mapnik/json/feature_generator_grammar_impl.hpp
+++ b/include/mapnik/json/feature_generator_grammar_impl.hpp
@@ -89,7 +89,7 @@ feature_generator_grammar<OutputIterator>::feature_generator_grammar()
     pair = lit('"')
         << kstring[_1 = boost::phoenix::at_c<0>(_val)] << lit('"')
         << lit(':')
-        << value[_1 = extract_string_(value_base_(at_c<1>(_val)))]
+        << value[_1 = extract_string_(at_c<1>(_val))]
         ;
 
     value = eps(at_c<1>(_val)) << escaped_string_(quote_.c_str())[_1 = at_c<0>(_val)]
diff --git a/include/mapnik/json/feature_grammar.hpp b/include/mapnik/json/feature_grammar.hpp
index a6a047dc0..a2d603664 100644
--- a/include/mapnik/json/feature_grammar.hpp
+++ b/include/mapnik/json/feature_grammar.hpp
@@ -70,7 +70,7 @@ struct put_property
     explicit put_property(mapnik::transcoder const& tr)
         : tr_(tr) {}
     template <typename T0,typename T1, typename T2>
-    result_type operator() (T0 & feature, T1 const& key, T2 const& val) const
+    result_type operator() (T0 & feature, T1 const& key, T2 && val) const
     {
         feature.put_new(key, mapnik::util::apply_visitor(attribute_value_visitor(tr_),val));
     }
@@ -104,7 +104,7 @@ struct feature_grammar :
 
     qi::rule<Iterator,void(FeatureType &),space_type> properties;
     qi::rule<Iterator,qi::locals<std::string>, void(FeatureType &),space_type> attributes;
-    qi::rule<Iterator, mapnik::util::variant<value_null,bool,value_integer,value_double,std::string>(), space_type> attribute_value;
+    qi::rule<Iterator, mapnik::util::variant<value_null,value_double,value_integer, bool, std::string>(), space_type> attribute_value;
 
     phoenix::function<put_property> put_property_;
     phoenix::function<extract_geometry> extract_geometry_;
diff --git a/include/mapnik/json/generic_json.hpp b/include/mapnik/json/generic_json.hpp
index d0533a379..1e696eb8f 100644
--- a/include/mapnik/json/generic_json.hpp
+++ b/include/mapnik/json/generic_json.hpp
@@ -41,8 +41,10 @@ struct generic_json
     qi::int_parser<mapnik::value_integer,10,1,-1> int__;
     qi::rule<Iterator,std::string(), space_type> string_;
     qi::rule<Iterator,space_type> key_value;
-    qi::rule<Iterator,mapnik::util::variant<value_null,bool,
-                                            value_integer,value_double,
+    qi::rule<Iterator,mapnik::util::variant<value_null,
+                                            value_double,
+                                            value_integer,
+                                            bool,
                                             std::string>(),space_type> number;
     qi::rule<Iterator,space_type> object;
     qi::rule<Iterator,space_type> array;
diff --git a/include/mapnik/json/topojson_grammar.hpp b/include/mapnik/json/topojson_grammar.hpp
index 1b5533611..d02289b4c 100644
--- a/include/mapnik/json/topojson_grammar.hpp
+++ b/include/mapnik/json/topojson_grammar.hpp
@@ -56,6 +56,21 @@ struct where_message
     }
 };
 
+namespace detail {
+
+template <typename T>
+struct value_converter
+{
+    using result_type = T;
+    template <typename T1>
+    result_type operator() (T1 const& val) const
+    {
+        return static_cast<result_type>(val);
+    }
+};
+
+}
+
 template <typename Iterator>
 struct topojson_grammar : qi::grammar<Iterator, space_type, topology()>
 
@@ -69,9 +84,7 @@ private:
     qi::int_parser<mapnik::value_integer,10,1,-1> int__;
     qi::rule<Iterator,std::string(), space_type> string_;
     qi::rule<Iterator,space_type> key_value;
-    qi::rule<Iterator,space_type, util::variant<value_null,bool,
-                                                value_integer,value_double,
-                                                std::string>()> number;
+    qi::rule<Iterator,space_type, mapnik::topojson::value()> number;
     qi::rule<Iterator,space_type> object;
     qi::rule<Iterator,space_type> array;
     qi::rule<Iterator,space_type> pairs;
@@ -102,7 +115,9 @@ private:
     qi::rule<Iterator, space_type, mapnik::topojson::value()> attribute_value;
     // id
     qi::rule<Iterator,space_type> id;
-
+    // conversions
+    boost::phoenix::function<detail::value_converter<mapnik::value_integer> > integer_converter;
+    boost::phoenix::function<detail::value_converter<mapnik::value_double> > double_converter;
     // error
     boost::phoenix::function<where_message> where_message_;
 };
diff --git a/include/mapnik/json/topojson_grammar_impl.hpp b/include/mapnik/json/topojson_grammar_impl.hpp
index d52641e57..34fa8a636 100644
--- a/include/mapnik/json/topojson_grammar_impl.hpp
+++ b/include/mapnik/json/topojson_grammar_impl.hpp
@@ -49,7 +49,7 @@ topojson_grammar<Iterator>::topojson_grammar()
     using qi::fail;
     using qi::on_error;
     using phoenix::push_back;
-
+    using phoenix::construct;
     // generic json types
     value = object | array | string_ | number
         ;
@@ -68,11 +68,11 @@ topojson_grammar<Iterator>::topojson_grammar()
         >> lit(']')
         ;
 
-    number %= strict_double
-        | int__
+    number = strict_double[_val = double_converter(_1)]
+        | int__[_val = integer_converter(_1)]
         | lit("true")[_val = true]
         | lit("false")[_val = false]
-        | lit("null")
+        | lit("null")[_val = construct<value_null>()]
         ;
 
     unesc_char.add
diff --git a/include/mapnik/json/topology.hpp b/include/mapnik/json/topology.hpp
index e7605a302..fda5c4962 100644
--- a/include/mapnik/json/topology.hpp
+++ b/include/mapnik/json/topology.hpp
@@ -43,7 +43,7 @@ struct coordinate
     double y;
 };
 
-using value = mapnik::util::variant<value_null,bool,value_integer,value_double,std::string>;
+using value = mapnik::util::variant<value_null,bool,value_double,value_integer,std::string>;
 using property = std::tuple<std::string, value >;
 using properties = std::vector<property>;
 
diff --git a/include/mapnik/value.hpp b/include/mapnik/value.hpp
index 3df89f45c..dc64ab609 100644
--- a/include/mapnik/value.hpp
+++ b/include/mapnik/value.hpp
@@ -799,9 +799,8 @@ struct to_expression_string : public util::static_visitor<std::string>
 
 namespace value_adl_barrier {
 
-class value
+class value : public value_base
 {
-    value_base base_;
     friend const value operator+(value const&,value const&);
     friend const value operator-(value const&,value const&);
     friend const value operator*(value const&,value const&);
@@ -810,64 +809,55 @@ class value
 
 public:
     value () noexcept //-- comment out for VC++11
-        : base_(value_null()) {}
+        : value_base(value_null()) {}
+
+    value (value const& other) = default;
+
+    value( value && other) noexcept = default;
 
     template <typename T>
     value ( T const& val)
-        : base_(typename detail::mapnik_value_type<T>::type(val)) {}
+        : value_base(typename detail::mapnik_value_type<T>::type(val)) {}
 
-    value (value const& other)
-        : base_(other.base_) {}
+    template <typename T>
+    value ( T && val)
+        : value_base(std::move(typename detail::mapnik_value_type<T>::type(val))) {}
 
-    value & operator=( value const& other)
-    {
-        if (this == &other)
-            return *this;
-        base_ = other.base_;
-        return *this;
-    }
-
-    value( value && other) noexcept
-        :  base_(std::move(other.base_)) {}
+    value & operator=( value const& other) = default;
 
     bool operator==(value const& other) const
     {
-        return util::apply_visitor(impl::equals(),base_,other.base_);
+        return util::apply_visitor(impl::equals(),*this,other);
     }
 
     bool operator!=(value const& other) const
     {
-        return util::apply_visitor(impl::not_equals(),base_,other.base_);
+        return util::apply_visitor(impl::not_equals(),*this,other);
     }
 
     bool operator>(value const& other) const
     {
-        return util::apply_visitor(impl::greater_than(),base_,other.base_);
+        return util::apply_visitor(impl::greater_than(),*this,other);
     }
 
     bool operator>=(value const& other) const
     {
-        return util::apply_visitor(impl::greater_or_equal(),base_,other.base_);
+        return util::apply_visitor(impl::greater_or_equal(),*this,other);
     }
 
     bool operator<(value const& other) const
     {
-        return util::apply_visitor(impl::less_than(),base_,other.base_);
+        return util::apply_visitor(impl::less_than(),*this,other);
     }
 
     bool operator<=(value const& other) const
     {
-        return util::apply_visitor(impl::less_or_equal(),base_,other.base_);
+        return util::apply_visitor(impl::less_or_equal(),*this,other);
     }
 
     value operator- () const
     {
-        return util::apply_visitor(impl::negate<value>(), base_);
-    }
-
-    value_base const& base() const
-    {
-        return base_;
+        return util::apply_visitor(impl::negate<value>(), *this);
     }
 
     bool is_null() const;
@@ -875,68 +865,67 @@ public:
     template <typename T>
     T convert() const
     {
-        return util::apply_visitor(impl::convert<T>(),base_);
+        return util::apply_visitor(impl::convert<T>(),*this);
     }
 
     value_bool to_bool() const
     {
-        return util::apply_visitor(impl::convert<value_bool>(),base_);
+        return util::apply_visitor(impl::convert<value_bool>(),*this);
     }
 
     std::string to_expression_string(char quote = '\'') const
     {
-        return util::apply_visitor(impl::to_expression_string(quote),base_);
+        return util::apply_visitor(impl::to_expression_string(quote),*this);
     }
 
     std::string to_string() const
     {
-        return util::apply_visitor(impl::convert<std::string>(),base_);
+        return util::apply_visitor(impl::convert<std::string>(),*this);
     }
 
     value_unicode_string to_unicode() const
     {
-        return util::apply_visitor(impl::to_unicode(),base_);
+        return util::apply_visitor(impl::to_unicode(),*this);
     }
 
     value_double to_double() const
     {
-        return util::apply_visitor(impl::convert<value_double>(),base_);
+        return util::apply_visitor(impl::convert<value_double>(),*this);
     }
 
     value_integer to_int() const
     {
-        return util::apply_visitor(impl::convert<value_integer>(),base_);
+        return util::apply_visitor(impl::convert<value_integer>(),*this);
     }
 };
 
 inline const value operator+(value const& p1,value const& p2)
 {
-
-    return value(util::apply_visitor(impl::add<value>(),p1.base_, p2.base_));
+    return value(util::apply_visitor(impl::add<value>(),p1, p2));
 }
 
 inline const value operator-(value const& p1,value const& p2)
 {
 
-    return value(util::apply_visitor(impl::sub<value>(),p1.base_, p2.base_));
+    return value(util::apply_visitor(impl::sub<value>(),p1, p2));
 }
 
 inline const value operator*(value const& p1,value const& p2)
 {
 
-    return value(util::apply_visitor(impl::mult<value>(),p1.base_, p2.base_));
+    return value(util::apply_visitor(impl::mult<value>(),p1, p2));
 }
 
 inline const value operator/(value const& p1,value const& p2)
 {
 
-    return value(util::apply_visitor(impl::div<value>(),p1.base_, p2.base_));
+    return value(util::apply_visitor(impl::div<value>(),p1, p2));
 }
 
 inline const value operator%(value const& p1,value const& p2)
 {
 
-    return value(util::apply_visitor(impl::mod<value>(),p1.base_, p2.base_));
+    return value(util::apply_visitor(impl::mod<value>(),p1, p2));
 }
 
 template <typename charT, typename traits>
@@ -948,12 +937,6 @@ operator << (std::basic_ostream<charT,traits>& out,
     return out;
 }
 
-// hash function
-inline std::size_t hash_value(value const& val)
-{
-    return hash_value(val.base());
-}
-
 } // namespace value_adl_barrier
 
 using value_adl_barrier::value;
@@ -984,7 +967,7 @@ struct is_null_visitor : public util::static_visitor<bool>
 
 inline bool value::is_null() const
 {
-    return util::apply_visitor(mapnik::detail::is_null_visitor(), base_);
+    return util::apply_visitor(mapnik::detail::is_null_visitor(), *this);
 }
 
 } // namespace mapnik
diff --git a/include/mapnik/value_types.hpp b/include/mapnik/value_types.hpp
index ecba8ef71..4288c389f 100644
--- a/include/mapnik/value_types.hpp
+++ b/include/mapnik/value_types.hpp
@@ -199,7 +199,7 @@ struct mapnik_value_type<T, typename std::enable_if<detail::is_value_double<T>::
 template <typename T>
 struct mapnik_value_type<T, typename std::enable_if<detail::is_value_unicode_string<T>::value>::type>
 {
-    using type = mapnik::value_unicode_string;
+    using type = mapnik::value_unicode_string const&;
 };
 
 } // namespace detail
diff --git a/plugins/input/geojson/geojson_datasource.cpp b/plugins/input/geojson/geojson_datasource.cpp
index 34aeb01ca..60751edc9 100644
--- a/plugins/input/geojson/geojson_datasource.cpp
+++ b/plugins/input/geojson/geojson_datasource.cpp
@@ -177,7 +177,7 @@ void geojson_datasource::parse_geojson(T const& buffer)
             {
                 desc_.add_descriptor(mapnik::attribute_descriptor(std::get<0>(kv),
                                                                   mapnik::util::apply_visitor(attr_value_converter(),
-                                                                                              std::get<1>(kv).base())));
+                                                                                              std::get<1>(kv))));
             }
         }
         else